118 REPORT— 1869. 



of the West-Indian Islands in the prevalence of species of Cylindrella, Macroceramus, 

 Ada>nsieUa,3Ie[/alomadoma, Chondropoma, Cistula, and Tudora, none of which genera 

 have been observed in Nicaragua, and south to the Isthmus of Darien. This cir- 

 cumstance, \iewed in connexion with the distribution of the Nicaraguan species, 

 points to a different origin for the fauna, and the author is thereby induced to regard 

 Nicaragua as comprised within the Columbian region of the distribution of land 

 and freshwater shells, and not within the Mexican. 



On the Effect of Legislation on the Extinction of Animals. 

 By the Eev. H. B. Teistkam, LL.D., F.'R.S. 



Five Years^ Experience in Artificial Fish-hreedinri , showing in what waters 

 Trout will and will not thrive, with some Remarhs on Fish and British 

 Fisheries. B>/ W. F. Webb, F.E.G.S. 



This paper gives the result of many experiments conducted by the author at 

 Newstead Abbey, both in lakes and streams, by which it is evident that tempera- 

 ture is the main point to study. Trout will thrive well in waters the midsummer 

 temperature of which does not exceed 62°, but when it attains 70° and upwards 

 they sicken and die off, even in swift-running streams. The author demonstrates, 

 by numerous examples, that both trout and all the Salmonidfe inhabit and thrive 

 best in waters of low temperature in every part that they are indigenous to. The 

 paper strongly advises the introduction of tlie Indian ilahseer into the fresh waters 

 of Great Britain, as the author states, from personal experience, that it is a fish 

 attaining very great weight, excellent for the table, giving sport to the angler, 

 and from not being migi'ator3' in its habits, exempt from the destruction caused by 

 sewage at the mouths of many rivers. The paper concludes by pointing out the 

 great devastation caused by trawl-nets throughout the narrow Lochs of the Western 

 Highlands, and to the rapid decrease of small fry of all sorts of fish already from 

 this cause, which calls for the immediate attention of the Legislature. 



On a new Isopod from Flinder's Island. By Henkt Woodavaed, F.G.S. 



On Rhinodon typicus, the largest known SharJc. 

 By Professor E. Perceval Wright, F.L.S. 



Anatomy ain^d Physiology. 



Human Vaccine Lymi^h and Heifer Lymph compared. 

 By Henrt Blanc, M.D., F.R.G.S., Staff Assistant- Surgeon, Bombay Army. 



Compvdsory vaccination is a wise and proper measure, but this must be subordi- 

 nate to one essential condition, namely, that the vaccine lymph forced upon the 

 public shall be as pure and as perfect as we can obtain it. The present human 

 lymph does not possess these characters. This leads us to examine the two fol- 

 lowing important questions : — 



1. Can other than vaccine disease be transmitted by humanized vaccine lymph ? 



2. Is humanized lymph of long standing a trustworthy prophylactic against 

 smallpox ? 



If we can prove beyond reasonable doubt that the transmission of disease has 

 taken place, even if only in a few instances, these instances should render us less 

 positive in our denials when in presence of very strong probabilities only. 



Science acknowledges two orders of disease that have been transmitted by human 

 vaccine Ij'mph — certain affections of the skin, and syphilis. 



On the 3rd of August, Dr. Uepaul, the Director of Vaccination in France, in 

 concluding, at the Academy of Sledicine of Paiis, a very remarkable speech on 



